For over a century, skin hygiene, particularly of the hands, has been accepted as a primary mechanism for reducing contact with and fecal-oral transmission of infectious agents (see “Hygiene of the Skin: When is Clean Too Clean”, Elaine Larson, Emerging Infectious Diseases, Vol. 7, No. 2, March-April 2001, www.cdc.gov/ncidod/eid/vol7no2/larson.htm). Most prominent health organizations advocate the benefits of handwashing for the prevention of infectious agents found transiently on the hands or spread by the fecal-oral route or from the respiratory tract. The United States Food and Drug Administration (FDA), for instance, mandates the personal cleanliness of food employees who prepare and serve meals in restaurants, grocery stores and other venues. The FDA Model Food Code requires food employees to follow a prescribed cleaning regimen, including vigorous cleaning of the hands and exposed forearms immediately prior to and during food preparation as often as necessary to prevent cross contamination (see FDA 2001 Food Code—Chapter 2: Management and Personnel, Section 2-3).
Recognizing the established relationship between transmission of infectious pathogens and personal sanitation, many sanitary manufacturers have introduced sensor-activated fluid delivery devices that reduce user contact with the devices and the consequent transmission of deleterious pathogens. Many “touchless” sanitary devices exist (i.e., faucets, toilets and urinals) that employ sensors to detect a user's presence and dispense water in accordance with one or more preprogrammed variables, including but not limited to the anticipated frequency of operation, the duration of use and the volume of water needed for sufficient cleanliness. Upon detecting the user's presence, the sensors compare the conditions of use with the preprogrammed variables and transmit corresponding signals to one or more valves in electrical communication therewith. The signals open and close the valves accordingly to adjust the water volume, temperature and flow rate without manual adjustment by the user. Sensor-activated sanitary devices therefore reduce opportunities for cross contamination by promoting hands-free operation.
Automatic faucets are particularly prominent in professional, residential and commercial installations. Health care institutions (such as hospitals, clinics and doctors' offices), restaurants, caterers and individual homeowners have installed automatic faucets as a way to achieve hand sanitation with minimal faucet contact. Automatic faucets have been especially useful in residential and commercial kitchens in which multiple tasks inherent in proper food preparation promote cross contamination. Automatic faucets are also particularly prominent in hospitals and other health care facilities in which health care workers assisting multiple patients in a short time span regularly spread infection among patients and among themselves due to insufficient hand washing.
Conventional touchless faucets, however, have suffered several drawbacks. Upon their introduction, many faucets did not enable easy adjustment of water volume, temperature and/or flow rate, and most did not provide selection between automatic and manual modes. Several manufacturers have sought to overcome such drawbacks.
U.S. Pat. No. 4,604,764 discloses a fluid delivery system that can be manually or automatically controlled. The delivery system includes a body for directing fluid, a regulator that manually controls fluid flow though the body and a setscrew for releasably locking the regulator in an open position for continuous fluid flow. An electrically operated valve is provided that includes each of an automatically controlled circuit and a manually controlled circuit. A sensor coupled to the valve detects the presence of a user and produces a signal in response thereto. The sensor transmits the signal to a controller for opening and closing the valve accordingly. The setscrew is engaged when the manually controlled fluid flow circuit is closed, and the setscrew is released when the manually controlled fluid flow circuit is open. A key, screwdriver or similar implement may open the circuit.
U.S. Pat. No. 4,709,728 discloses a single-axis control automatic faucet having a manually actuatable valve, a solenoid valve and an infrared sensor for opening the solenoid valve upon detection of a user's hands. The faucet controls the release of water and further adjusts the water temperature via manual operation of a single-axis stem switch. In the event of a power interruption, automatic operation can be changed to manual operation by depressing the switch. Depression of the switch lowers a control stem and opens a valve port from which water is discharged continuously. Under this condition, unless the switch is manually pulled so as to close the valve port, water will flow continuously from the faucet. When power is supplied, depression of the switch enables automatic operation upon passage of a user's hand in proximity of the sensor. Upon removing the hand, the switch must be pulled up manually to fully close the valve port.
U.S. Pat. No. 4,962,790 discloses a faucet having interchangeable proximity actuation control and hand control for water flow. The faucet includes a hemispherical valve seat with two holes and two channels formed therein. A valve stem guide is provided that has an H-shaped guide groove formed therein to accommodate passage of a valve stem that is coupled to a handle. A bi-directional feed pipe has one end connected to a valve outlet hole that is opened or closed by a solenoid valve in electrical communication therewith. A second end of the feed pipe connects with a channel on the valve seat, and a pipe juncture formed on the feed pipe is connected with an outlet pipe. A sensor in electrical communication with the solenoid valve effects operation of the valve upon detection of a user within proximity of the sensor. The user turns the handle to match cold and hot water outlet channels with hot and cold water inlet holes so that the desired water temperature flows from the faucet upon the sensor's detection of the user. The user adjusts the water temperature by turning the handle clockwise or counterclockwise.
U.S. Pat. No. 5,351,347 discloses a proximity-controlled sanitary fitting having an electrically controlled valve body and an electric proximity detector in electrical communication therewith. The detector comprises a radiation-emitting transmitter that sends signals to a receiver. A sensor detects at least one of a user and a water level, produces an output control signal in correspondence therewith and transmits such signal to the valve. A manually operated handle that is operatively coupled to a switch controls operation of the proximity detector. The handle, which extends outwardly from a main body having a spout, is manually adjustable among a first position, in which the detector senses a user and provides an output signal to the valve; a second position, in which the valve is closed to prevent water flow; and a third position, in which the detector does not sense a user's presence and maintains the valve in an open position to permit continuous water flow. This configuration enables detection of the water volume in a wash basin and consequent cessation of water flow when a predetermined volume is attained.
Related U.S. Pat. Nos. 5,358,213, 5,397,099, 5,595,216 and 5,755,262 disclose a faucet having automatic and manual control capability. The disclosed faucet includes a body supporting a single flow control valve with a chamber defined therewithin and at least one inlet port and at least one outlet port. The valve further includes a positionable valve member that moves between a closed position, wherein the inlet and outlet ports are isolated from the chamber, and an open position, wherein the inlet and outlet ports are in open communication with the chamber. Each of a manual actuation mechanism (i.e., an operating lever) and an electrically operated automatic actuation mechanism (i.e., a solenoid) is coupled with the valve member for movement thereof, such that the automatic mechanism moves the valve member independent of the manual mechanism. A sink arrangement is also shown in which the disclosed faucet is positioned over each bowl of a sink. A detector is provided to ensure the discharge of the proper water volume in a selected bowl.
U.S. Pat. No. 6,003,170 discloses a single-lever faucet assembly having a conduit defining a flow path between a water supply and an outlet. Each of a mechanical valve and a servo-valve is disposed in the conduit. A lever coupled to the mechanical valve moves the mechanical valve between open and closed positions. A proximity detector is also provided in electrical communication with a controller that is also coupled to the servo-valve. Upon detection of an object in its proximity, the detector transmits a signal to open the servo-valve. A position-detecting switch in communication with the mechanical valve and the controller maintains activation of the controller upon shifting of the mechanical valve into its open position and deactivation of the controller upon shifting of the mechanical valve into its closed position. In this configuration, as soon as a user touches the handle is touched, the controller opens the solenoid valve and starts monitoring the sensor. The faucet therefore operates like a standard faucet except that it will turn itself off after a predetermined duration if no contact is made with the handle. To restore fluid flow, the user touches the handle, such that the proximity detector only shuts the water off when the faucet is not in use.
U.S. Pat. No. 6,044,865 discloses a single-lever mixer having a housing part with a mixer tap disposed therein. A control rod that is coupled to an actuating lever effects actuation of the mixer tap between a final closed position and a final open position. An electrically controllable valve is fitted downstream of the mixer tap and is electrically coupled to a proximity sensor. The actuating lever manually controls the electrical valve through a lever arrangement coupled between the control rod and the electrical valve. Adjustment is achieved such that in the mixer tap's final closed position (or within a first pivot range of the actuating lever), the valve remains closed; in the mixer tap's final open position (or within a third pivot range of the lever), the valve remains open; and within a second pivot range of the actuating lever, the valve remains closed and is opened only by activation of the proximity sensor.
U.S. Pat. No. 6,341,389 discloses a faucet assembly having a housing with an outlet and a servovalve disposed in a conduit that defines a flow path from a water supply through the housing to the outlet. A manual valve that is also disposed in the conduit has a control element movable among open, intermediate and closed positions. A position detecting switch subassembly mounted on the housing engages the control element, and a proximity detector is provided that has a detection field adjacent the outlet. A controller coupled to the proximity detector, the switch subassembly and the servovalve deactivates the detector and closes the servovalve when the control element is in the closed position. When the control element is in the intermediate position, the controller opens the servovalve upon sensing a user in the detection field. When the control element is in the open position, the controller disables the detector and opens the servovalve thereby.
U.S. Pat. No. 6,363,549 discloses a faucet system including a manually controlled valve having a handle for controlling fluid flow between an inlet and an outlet. The faucet also includes an electrically controlled valve hydraulically in series with the manual valve. A first sensor is provided that detects a user's presence in the vicinity of the manual valve, and a second sensor is provided that detects user contact with the handle. An electronic controller is coupled to the electrical valve and the first and second sensors such that the second sensor is hierarchically superordinate to the first sensor, thereby keeping the electrical valve open as long as there is contact with the handle. The first sensor is hierarchically subordinate to the second sensor, thereby keeping the electrical valve open in the absence of handle contact and with continuous activation of the first sensor.
U.S. Pat. No. 6,390,125 discloses a faucet valve system having a lever-operated valve with a housing formed with a water outlet. At least one water inlet communicates with the housing, and a valve member is disposed in the housing between the inlet and the outlet. A control lever is provided that is movable about an axis transverse to the housing's central axis. A detent member in the housing is formed with a detent opening along an arcuate path of the lever. The detent member includes a spring-loaded detent body bearing thereon that engages in the detent opening upon displacement of the lever about its pivot axis to a predetermined angular position for opening the valve member. An electric circuit is provided that responds to the angular displacement and includes at least one further valve in series with the lever-operated valve for controlling fluid flow from the outlet. The further valve has a control coupled to a detector that maintains the further valve open for a duration determined by activation of the detector. A switch in the housing is connected with the control for rendering the detector effective in the lever's predetermined angular position and rendering the detector ineffective in other angular positions.
None of these improvements in touchless technology discloses a fluid delivery device that eliminates contact with the device in an automatic mode, yet still delivers water having desired temperature, volume and fluid flow characteristics. At installations where automatic faucets are prevalent (such as restaurants and health care facilities), extensive research has revealed that professionals in those facilities actually wash their hands for a shorter period of time than required by prevailing health codes. Such individuals cite the faucets' inability to provide water flow at a predictable temperature, volume and flow rate, as well as significant time lapses between placement of the user's hands in a sensor's detection zone and initial water flow onto the hands. These conventional faucets incur delays in the professionals' schedules and deliver water at uncomfortable temperatures and pressures. These professionals do not have extra time between tasks for adjusting water flow conditions, and in many cases, the faucet is not amenable to such changes without faucet contact. Faucet contact and delays in water delivery encourage these professionals to reduce handwashing duration or eliminate washing altogether, thereby obviating any hygienic benefit provided by the automatic nature of the faucet.
It is therefore desirable to provide a selectively operable proximity faucet that overcomes the above-cited shortcomings. It is further desirable to provide such a faucet that permits easy selection between fully manual and fully automatic modes without adjustment of the proximity detector and without hand contact on any portion of the faucet while in the automatic mode.